THE TOM SWIFT INVENTION ADVENTURES

TOM SWIFT

IN THE UNDERLANDS OF MARS

BY VICTOR APPLETON II

"YOU MEAN we’re not going to Mars after all?" demanded Bud Barclay, amazed and angry.

"That’s not what I’m saying," responded Tom Swift to his best friend. "Give me a chance to explain."

The famous young inventor stood facing the assembled crew of the Starward, the huge new spacecraft developed by Tom Swift Enterprises under the direction of Tom and his father. Their young commander had called all ten astronauts—a select team of space veterans and scientists—to join him on the ship’s broad observation deck to announce a change in the goals of Enterprises’ latest bold scientific venture, a two-week research mission to the arid surface of Earth’s neighbor, Mars. It had been only minutes since the Starward had broken from its parking orbit about our world and begun its trajectory to the Red Planet.

Behind the crew rose the ship’s curving viewport, almost three stories high and cutting vertically across several open-sided decks of the great sphere-shaped vehicle. Tom paused, the slowly diminishing Earth swimming before him against an icy tapestry of stars. "I said there would be a change, that’s all. The mission is continuing."

"All right, boss. Then what’s this all about?" The speaker, Lori Matthews, stood at the front of the group and spoke calmly—more calmly than Tom’s emotional, impulsive pal Bud.

Tom’s reply was grim. "This is still a scientific expedition. But now—it’s also a rescue mission."

Surprise flashed across the collective face of the crowd. The familiar gravel-toned voice of big Chow Winkler broke the moment of stunned silence. "Rescue? Wa-aal brand me fer a heifer, jest who is it we’re s’posed t’ be rescuin’? One o’ them blame Martian space friends o’ yours?"

Shaking his head, Tom gestured toward the one member of the crowd who was unfamiliar to everyone but Tom himself. "Dr. Yun? Perhaps you should answer."

The stout Korean biologist, black hair streaked with stark-white cords like bolts of lightning, stepped forward and turned to face the others. "You do not know me, ladies and gentlemen, although we are colleagues and companions on this journey. I am Yun Dai Koh, of the Korean National Institute for Advanced Sciences, as you would say it. It was only within the last four days that my government contacted your own to request—indeed, to beg for—a place aboard this ship. Young Mr. Swift and his father were pledged to absolute secrecy, and they gave their solemn word of honor when our purpose was explained to them. We were most grateful that they were willing to modify the itinerary of this long-planned project of Swift Enterprises and your NASA space agency."

Ever since the day Tom’s Challenger spaceship had carried the young scientist-inventor to the surface of the moon, Tom had known that a voyage to nearby Mars would be an inevitable further step into interplanetary space. With the development of his revolutionary cosmotron propulsion system, installed aboard the Starward and given its trial run on a circuit of the outer Solar System, he and his father had directed the formidable forces of Enterprises toward this next extraordinary quest for knowledge. The announced plan called for a landing on the Martian surface, establishment of a base camp, and a stay of perhaps fourteen days duration. Two new inventions of Tom’s—a support suit for explorers and a flying scout vehicle making use of advanced principles—were to be tested on the frigid plains of the dry, dusty, all-but-airless planet.

Beyond the scientific investigation of the Martian environment, the Swifts had identified one further extraordinary mission goal. Achieving this goal had a personal edge to it. During the course of their stay Tom hoped to find definite evidence of intelligent life on Mars, an alien civilization that had been detected in the early Twentieth Century by the youth’s great-grandfather, the legendary Tom Swift who first gained the world’s attention for his remarkable inventiveness. Tom’s namesake had been unable to replicate his findings before a skeptical world, compromising his reputation in the later years of his life. Even though robotic surveys of Mars had as yet shown no trace of life or intelligence, young Tom hoped to redeem his great-grandfather’s name.

But now the space team wondered if Dr. Yun was about to announce something that would interfere with this aspect of the historic project.

"I will assume you are all familiar with the fate of the prior attempt to place humanity on Mars. I refer, of course, to the Red Eye ex-pedition."

The crowd muttered restlessly. "Of course we know about it," declared Tom’s chief engineer Hank Sterling. "Who doesn’t? It was a world tragedy."

"Yes, indeed so," agreed Dr. Yun in his clipped accented tones. "Forgive me if I recount a brief summary of this sad, famous affair.

"The Red Eye, words that translate a tra-ditional Chinese name for the planet Mars, was the project of the Eastern Nations Consortium of Space Sciences, as it is known to you in English—that is, ENCOSS. Seven Asian nations joined together, with the support of their respective governments, to plan and mount this space effort. Some have said that regional pride, a wish to compete with the announced planetary goals of Europe and America, lay behind all this; and some have added that perhaps it was undue haste and lack of proper testing that led to the resultant human disaster. Of that, I know nothing. My own role in the operation, as an employee of the Institute, was very slight.

"The Red Eye craft left Earth orbit without incident, bearing its crew of seven outward toward Mars, propelled by a solar-sail method. As you know, the transit lasted more than a year. Finally the landing module parachuted into the very thin planetary atmosphere—or at least, that was what was anticipated.

"Atmospheric penetration was to take place on the side of the planet then turned away from the Earth. It was expected that confirmation of a successful landing, by radio transmission, would come after a gap of several hours while that part of the surface rotated into position. Yet I have no doubt you all remember the silence, dreadful silence, hour after hour, day after day.

"Telemetry from the various photographic drones then circling the planet showed no sign of wreckage. It was ultimately concluded that the Red Eye had exploded during the initiation of powered retro-descent, which used rocket thrust engines following ejection of the parachute array. Subsequently the fragments of the capsule would have burned to cinders by the friction of its uncontrolled fall through the atmosphere." Yun added: "So it was thought."

"You’re saying that’s not what happened?" asked Bud skeptically. "But Tom himself surveyed the area—"

Tom interrupted. "That’s right. During the course of our initial unsuccessful Mars-scan for signs of intelligent life, we used my megascope space prober to examine the entire region for any trace of wreckage, or any sort of recent impact crater or burn mark. We found nothing."

"Then what’s with the rescue bit?" persisted Bud heatedly. "There couldn’t possibly be any survivors down there! I mean, jetz! Even if they managed to make it down to the ground, it’s been years now!"

Dr. Yun gave a thoughtful nod of acknowledgement. "Your objection is surely well taken, young man. At the Institute which employs me, which established an astronautics program to honor the memory of the lost astronauts and continue the cooperative multi-nation endeavors of ENCOSS, there was no thought of even the bare possibility of survival. In the event of a successful landing, the crew had brought with them only about twenty-six months’ worth of provisions, just long enough to await the time when the planet would again be at close proximity to Earth and the long return voyage could commence. Now it has been, as Mr. Barclay points out, a good number of years since that day. And so you can well imagine our surprise—indeed, our disbelieving aston-ishment!—when the radioscopic detector instruments of the ENCOSS organization—"

He paused, and Tom continued the thought. "A signal! They’ve picked up a signal from survivors—on the surface of Mars!"

ONLY dry cabin air whooshed into, or out of, the gaping mouths of the stunned listeners. No one spoke aloud.

Unsurprisingly, it was Chow who broke the silence. "You tellin’ us—those poor people’re still alive up there on that planet? But how th’ hey did they pull it off?"

"Just what was the message they sent, anyway?" asked Neil MacColter, one of Enter-prises’ top veteran spacemen. "Did they explain what happened to them?"

Tom answered for Dr. Yun. "The signal only lasted for about 18 seconds, and carried no vocal info."

"It was the locator beacon signal from the lander capsule," continued Yun. "It was unmodulated, but the frequency profile could not be mistaken."

"Hoax is the most likely explanation," snapped physicist Rafe Franzenberg, a char-acteristically blunt-spoken man.

"That would be as impossible as the event itself, sir. Brief as the signal was, our instruments were able to triangulate upon the emission source on the Martian surface. Even over 18 seconds there was a slight shift due to the planet’s normal rotation." Bud asked if the precise location on the surface had been pinpointed. "No, not pin-pointed, as you put it. But it was in the general area where the Red Eye would have touched down—within three or four horizons, so to speak."

"All right," Hank said. "Let’s assume the signal was genuine and some part of the expedition has survived. What’s the plan from here on out?" The young engineer pointedly turned his gaze toward Tom.

"No immediate change," pronounced Tom. "We’ll pull the Starward into orbit, then descend down to the surface in Mod 2 and set up our base camp. It’s just that we’ll be landing in a different part of Mars. We’ll still be able to collect our data while we search for the Red Eye capsule."

"It’s your decision, skipper," Neil stated to a smattering of quiet applause and nods.

"Thanks, fellows. Dad and I know we can always count on all of you—no matter what we end up putting you through." Tom dismissed the crew to their many tasks. But as they scattered, Dr. Yun joining them, Bud and Chow dawdled behind.

Bud was glowering. "Tom—you could have told me."

"We don’t keep secrets from each other," conceded the young inventor apologetically. "I’m sorry, flyboy."

"Now you hold off there, Buddy Boy," Chow remonstrated. "Tom and his Dad gave their words, sounds like. You cain’t ask ’em t’go against that—not those two."

"Yeah. I know." Bud gave up his moment of pique with a half-shrug. He couldn’t stay angry at his pal for long. "But you haven’t explained the need for the secrecy."

"That’s purt’ much what I’d like to know!" Chow put in. "Seems like we ’as jest doin’ a pure good deed, plain an’ simple. Folks all around the world would be glad if we got ’em back, wudden they? Not like we’re overstocked with heroes back home—not even in Texas!"

Tom lowered his voice to a near-whisper and motioned his friends forward, into a huddle. "I’d rather not go into this in front of the rest of the crew."

Bud groaned softly. "I can see it coming a parsec away! Spies, saboteurs, all that bad-guy stuff—right?"

As Tom nodded with a wry grin, Chow said: "Still don’t make no sense t’ ole Chow, boys. Jest why’d anybody want us not to rescue those foreign folks?"

"I can only tell you what I know—what the Korean officials told Dad and I. In these last few days there have been attempts on the life of everyone who knows about that beacon signal."

"What!" gulped Bud, eyes as wide as Chow’s—which was wide indeed.

Tom nodded soberly. "There were a half-dozen people at the ENCOSS lab involved in processing the signal, including Dr. Yun, who’s been using radio-telescope data, and our own Enterprises telesampler device, to search for organic compounds in interplanetary dust. These six then informed two key members of the Institute. After consultation with the government, the scientists were told to maintain absolute secrecy for the time being—to prevent a media frenzy, I guess. Yet within hours of identifying the signal peculiar things began to happen. Car brakes went out, lab fires broke out, home windows were shot out—"

"I get the idea!" Bud whisper-shouted.

"There was an attack on a man working late at the Institute, by an unidentified masked assailant. And Dr. Yun survived what looks like a knifing, while he was walking through a crowd. Three of the eight are now hospitalized with serious injuries, and one other died from a bullet wound. In other words," Tom pronounced, "whoever’s behind this is aiming at murder!"

Chow Winkler, the expedition’s cook, had turned as white as flour-sifted bread dough. "Good gravy, sure sounds like it! And nobody knows who er why, boss?"

"Not a clue," confirmed the crewcut young inventor. "Our own top-secret sources contacted me to let me know that even they are stumped on this one, for once." He reminded his listeners that the attacks on the science team had begun even before the Korean government had been con-tacted. "Someone with immediate access to ENCOSS’s instrument data must have ‘tagged’ the event. But no one knows why—or how they found out in the first place, assuming the plotter isn’t one of the original eight. Because the scope of the enemy’s spy technique isn’t known, the two governments agreed to a high level of secrecy until the Starward was off to Mars." Tom concluded, "And that’s the story, you two."

Bud’s face told Tom he was feeling abashed even before he spoke. "Well, then, I guess the secrecy may have been a good idea." The black lock of hair flopping across the youthful pilot’s forehead seemed to droop further than usual. "I mean—they could have been bugging me. Or Chow."

"Or anyone, as far as we know," said Tom with a sympathetic smile. "But now that we’re under way, it doesn’t matter. Nobody can get at us in space."

"Mebbe so t’ that, but it’s sure still a blame mystery!" Chow noted. "I’m gonna watch my back. —An’ whatever yuh’re thinkin’, Buddy Boy, jest toss ’er back fer once!" Bud’s affec-tionate cracks at the expense of Chow’s ample breadth were easy to predict.

Now that the Starward had passed beyond the critical point of Earth’s gravity "well," her bank of force-ray repelatrons was shut down and the ship’s cosmotron spacedriver was activated. As the revolutionary device grabbed ahold of the fabric of spacetime, the huge craft shot forward almost instantly, traversing thousands of astral miles in a matter of seconds without the slightest jolt to those aboard. Standing at the main control board next to Neil MacColter, pilot and navigator for the voyage, Tom picked up a microphone and announced to the crew: "We’re nominal for the main traverse, folks. We look to be entering Mars orbit in about three hours or so."

With time to kill, Tom and Bud went to the communications compartment. "Much as I like saying Hi to Sandy," said Bud, "I’ll bet she’s madder than a dunked kitten at being left out of the loop." His pal agreed with a laugh.

At the main panel Tom selected one of several cartridge-like containers from a rack and clicked it into place in a port on the board. Each cartridge contained a matrix of subatomic particles that allowed it to forge a unique quantum link to exactly one counterpart cartridge back on Earth—in this case, inside a unit that Tom knew was, at the moment, in the Swift home in Shopton. The family would be expecting this word from space.

Almost as soon as the PER—Private Ear Radio, the nickname used nearly always in lieu of the official mouthful, "parallelophone"—had established its connection, the voice of Tom’s father came through loud, clear, and instan-taneous. "We’ve all been sitting in the living room with our eyes on the com unit, son," said Damon Swift. "Your mother and sister were getting a bit restless."

"Not you, Dad?" Tom joked.

"Certainly not."

The two scientist-inventors spoke for a moment of various technical matters. Then the PER was handed to Tom’s mother, and then to his vivacious sister Sandra. At the moment her vivacity evidenced a bit of an edge. "Tom Swift! How am I going to face Bashi, having to tell her that my own beloved brother wasn’t willing to leak a few scraps of this delicious murder-mystery-plot stuff! I hope you realize, Tomonomo—I probably could’ve solved the whole thing for you before you even left."

"Our loss, San," replied Tom with a chuckle at Sandy’s pretended outrage. "I know Dad’s explained the reason. As for Bash, I’ll just bet she’s standing there right next to you. Am I right?"

"You are annoyingly right, as usual," came the voice of the pretty young Pakistani, close friend to Tom and the family—in which Bud was included by popular demand. "Sandra is livid, but I am quite willing to forgive you for making her so. But—but Tom—" Bashalli Prandit continued, suddenly hesitant with emotion, "are you quite sure you’re out of danger up there on Mars?"

"Hey, don’t worry, Bash," Bud chirped in. "Any big multi-armed Green Martians we come across’ll be sent packing by one of Tom’s x-raser disintegrator rays!"

"I am now so comforted, Budworth."

Incredibly soon the Starward had put more than 300,000,000 miles behind it and was beginning its approach to the Red Planet. In anticipation Bud and several crew members had joined Tom on the main deck at the control panel. Mars had swollen to the size of a quarter at arm’s-length, revealing its mottled surface of pale brick highland plains and the darker shades of the lowlands.

Suddenly Neil called out quietly, "Tom, take a look at the scope." He gestured at the radar monitor, where a small patch of white had appeared.

"What is it?" asked Rafael Franzenberg.

"Not a matter of concern, I hope," added Dr. Yun fretfully. Despite his outward calm, the voice of the Korean scientist bespoke the anxiety inherent in his first trip into space.

Tom studied the radar bogie. Then he smiled. "No, it’s not a danger—in fact, I think it’s something interesting. Neil, let’s overtake it and pull up close."

The astronauts were soon confronted by a huge, circular object floating in the void, slowly rotating. Resembling a ribbed umbrella, it was many-sided but basically disklike, stark white in color, slightly parabolic. "Good night!" Bud exclaimed, "it’s bigger than a football field!"

"Bigger than two American football fields, in fact," corrected Dr. Yun. "It is the discarded solar sail from the Red Eye."

"It’s been floating out here all this time?" wondered Hank Sterling.

"Indeed so, in a high-ended elliptical orbit about Mars, which sunlight pressure has further distorted over the years. After returning to space, the Red Eye landing module would have recon-nected with it for the return trip, tacking like a sailboat in the unceasing wind of light."

Fascinated, Tom directed Neil to guide the spaceship closer. "Let’s do a photo study to take back to Earth," he commented.

They drew up to within one hundred feet, the sail extending off to its own horizon, a great curving expanse of shining white that made them shade their eyes.

Abruptly Bud exclaimed, "Hey, what’s up with that?" A tall and growing ripple, like a plasti-foil tidal wave, was sweeping across the surface of the sail in their direction.

"My gosh, it’s accelerating! It’ll hit us if we don’t put on a little distance," declared Neil. He activated the space-driver engine to move the Starward out of the way.

But the action came too late! To the shouts of the started crew, one edge of the Red Eye’s sail suddenly curved up in a great lunge and slapped against the hull of the ship like a flyswatter against a fly!

THE IMPACT was as violent as it was unexpected. Tom and his fellow astronauts were knocked off their feet, sliding together against the compartment bulkhead in a tangled heap. Like a giant’s soccer ball the Starward rocked and somersaulted backwards away from the solar sail.

Niel MacColter leapt at the controls, but Bud was quicker. The youth’s hands flew over buttons and touch-pads, and finally grasped the unistick control lever, easing the great ship away from the sail and off into space.

"Good great grief!" exclaimed Hank. "What made the sail pull that stunt? Look, it’s still vibrating." The Red Eye sail was oscillating back and forth from edge to edge, wave after wave.

Returning the controls to Neil, Bud jerked a thumb toward an intercom speaker. "Shall we start a countdown?"

"Hey up there!" crackled a familiar bellow from the ship’s galley.

Tom approached the unit and pressed the mike button. "Chow, are you okay? Did the jolt damage anything?"

"Hunh? What jolt? I jest wanted t’ know when you plan to have lunch." As Bud’s eyebrows flew up in surprise, the big westerner broke out in a laugh. "Naw, I ’as jokin’ with ya. But brand my space-quakes, what was that anyhoo? We get hit by a meaty-er?"

"No, just a bolt of stupidity on the part of your captain," was Tom’s rueful reply. He turned to the others, keeping the voice circuit open so Chow could hear. "The ship’s big shadow is the culprit, folks. I forgot—when we cut off the pressure of the sunlight, it threw the structural tension on the sail out of balance."

"Yes, I see now," commented Dr. Yun. "As it began to distend, the change in angular momen-tum produced a self-reinforcing oscillation in the foil, which is extremely thin."

"Don’t have no idea what you fellers are jabbin’ about," commed Chow. "But boss?"

"Yes, pardner?"

They resumed their planned trajectory, and Tom was soon able to announce that the Starward was in orbit about Mars. "Well, look over there!" called out Lori Matthews, the team’s planetary geophysicist. "There’s Deimos—I recognize her from her publicity photos." For the benefit of those who were newcomers to the space neighborhood, she gave a brief description of the tiny, potato-shaped Martian moonlet, only about ten miles across. "Mostly made of meteor-type materials, according to our spectrometry readings."

"Not much to ’er," commented Bud.

"Well, look quick, Bud. Both Deimos and her big sister Phobos have deteriorating orbits. In a few million years they’ll take a swan-dive into the atmosphere."

"Do you plan a close pass?" Dr. Yun asked Tom. "Perhaps we might retrieve some surface samples to take back to Earth."

"Actually, we already have, by means of my telesampler." This invention of Tom’s allowed the excision of molecular samples from across the reaches of space.

"And besides, Dr. Yun, landing on Deimos—or even getting too close—is one thing our nice big cosmotron express can’t do," stated Mac-Colter in a serious tone of voice.

The Korean scientist looked puzzled. "Oh? But why is that, might I inquire?"

"It’s the space people," said Bud.

Tom explained. "Doctor, I know you know all about the Planet X scientists we call our space friends," he said to Yun. "They’ve made clear that they have some sort of base, or research installation, on Deimos—probably under the surface, as the megascope doesn’t show anything on the outside."

"They wish no visitors?"

"You might say that," replied the young inventor dryly. "Though they don’t seem able—or willing—to explain the situation, we’ve doped out that their superiors on their planet of origin have imposed a sort of ‘information quarantine’ on them. They are required, compelled actually, to be very secretive about the X-ian civilization, their technology, even their physical form. We know little of the purpose of their work in this solar system."

"But they shor do like t’ study us, jest like rats under a dang microscope," put in Chow, who had joined the group. "Don’t care a whit whether we like it er not!"

"That’s more or less true," Tom agreed. "We’ve suggested meeting them in space many times, and the message back is always something like ‘not possible to comply’."

Dr. Yun nodded. "I understand, Tom. And I presume you’ve asked them about the Red Eye?"

"Yes, just as soon as we found out about the possibility of survivors. They signaled back, ‘unable to provide requested data’. And when we told them of our planned Mars expedition," Tom continued, "they said: ‘extreme danger to you can not be contained if you approach within thirteen minor radii of the planet-four lesser satellite’—which means Deimos."

"I wonder what they’re afraid of," murmured Lori. "With all their super-technology, they act like scared space rabbits."

"That’s something we haven’t figured out," Tom stated. "For all we know it may be some sort of overpowering instinct for self-protection hardwired into their nervous systems."

"Anyway," said Bud, "if it’s privacy they want, I vote we give it to them!"

Tom had already programmed information on the revised landing site into the spaceship’s guidance computer. "We’ll touch down in a region called the Ophir Planum, near the edge of the cliffside of a deep gorge, the Coprates Chasma."

"Them places sound dangerous!" gulped Chow.

"The Chasma is like a long crack in the ground with high sides and a wide flat bottom," Lori Mathews explained. "It’s an offshoot of the Valles Marineris—Mariner Valley—which stretches almost halfway across the western hemisphere near the equator."

Dr. Yun interjected, "One of the goals of the Red Eye expedition was to study the topography of the Marineris region. It was thought that pockets of life might exist, warm and protected at the bottom of deep crevices."

The crew understood that the Starward itself would not descend from orbit. Instead they would touch down in one of the three smaller spherical modules attached to her hull. "So who’s gonna git left behind to watch the ship, boss?" Chow asked Tom. "Not me, I hope!"

Tom chuckled. "O’ course not, pardner—we have to eat, you know! Actually, no one needs to remain aboard the Starward. She’ll be safe up in orbit, and we can always access her controls and sensors remotely." The young inventor now turned to the others. The entire exploration team had assembled on deck, carrying their various items of specialized equipment like travelers’ suitcases. "All right, everyone, the landing site is just coming up on the horizon. Time to board Mod 2 and get going."

"What a strange, startling moment this is," muttered Dr. Yun. "Once I envied the men and women of the Red Eye as they left on their journey. And now I myself am here in their footsteps—on the threshold of Mars."

"I know the feeling, doctor," concurred Bud. "You never know what life has in store for you next. I’ve sure learned that, thanks to genius boy over there." Bud couldn’t help thinking for a moment of his many strange experiences at the side of his friend, from their first perilous adventure in South America in Tom’s Flying Lab to their recent involvement in political intrigue and nuclear blackmail, a plot foiled by the young prodigy’s remarkable thoughtograph imager.

With her crew of eleven aboard, Neil MacColter disconnected Excursion Module 2 from her recessed docking port at the summit of the Starward, moving off with a gentle nudge from the craft’s inbuilt bank of repelatrons. Mod 2 was shaped like a pintsized version of the multistory Starward, and like the mother ship a large part of her hull was covered by a huge rounded viewport of unbreakable Tomaquartz, coated with transparent Inertite for protection against cosmic rays.

As the repelatrons pushed against the far planet horizon ahead of them, the module lost its orbital speed and began to curve smoothly downwards. A slight vibration announced entry into the atmosphere.

"I thought the air here was ultra-thin," Bud noted with curiosity. "How come we’re feeling it so high up?"

"Ultra-thin it is," confirmed physicist Fran-zenberg. "Average surface pressure only about seven percent of Earth-normal."

"But that doesn’t make it any tamer, flyboy," Tom said. "Just the opposite—it’s so thin and dry that it’s subject to big variations in temperature across the planet. And with gravity so weak, there’s nothing to stop the winds from picking up quite a head of steam."

"Not that I’m worried," said Tom’s pal quickly and unconvincingly.

In minutes Neil announced that they were hovering a half-mile above the Ophir site. Tom gave the okay for a landing, and Mod 2 drifted down yard by yard, extending her curving landing struts. The landing was so soft and well-cushioned that the astronauts didn’t realize it had happened until Tom exclaimed: "Touchdown! We’re on Mars, space fans!" The control deck rang with cheers and excitement—yet everyone could feel a shadow falling across them as they gazed out at the eerie, silent world beyond the viewpane.

Mars awaited. But would it prove hospitable to the explorers and rescuers from distant Earth—or reveal itself as the Angry Red Planet of space legend?

BEFORE opening the main airlock hatch Tom spent a good twenty minutes reviewing the accumulated data from the various instruments that were continually sweeping the environment for any sign of unwelcome surprise. For this task Rafe Franzenberg and Hank Sterling were his expert assistants.

"What’s the verdict, skipper?" Hank inquired. "Can we start setting up camp?"

"I see no problems, Tom," added Rafe.

Tom nodded happily. "Neither do I. The Mod’s in perfect shape, windspeed is okay, tem-perature a scorching 38 degrees in early afternoon—and the penetradar shows we’re perched on good solid ground. Let’s open up and take a walk!"

Tom briefly contacted his family via PER to announce the safe arrival of the expedition. He then clicked a different cartridge in place and spoke to the Swift Enterprises liaison at NASA, who would inform the world media of the historic event.

Hearty congratulations ringing in his ear, the young space explorer directed the others to pull on their Mars-environment space outfits. "I’d like all of you to join me outside for our ceremony," he said. "But from here on out, let’s make a practice of always having one crew member stay behind while the rest are off safari-ing."

"Safer that way," commented Marlene Jencks, the project’s planetary meteorologist—whom Franzenberg called our lovely weather girl.

The group crowded into the outer hatch accessway and Tom activated the micromotors that swung the curving hatch out and sideways. There was no need for the usual airlock procedures—an invisible barrier of Inertite microfilaments sealed the open portal, preventing the craft’s internal air from bursting free, yet allowing human-sized objects easy passage.

After activating an automatic video setup, Tom led the others down the access ramp and onto the dry, dusty surface. The first human words from the surface of another planet were uttered by Tom Swift. "That’s it, everyone—life on Mars!"

"Huh? Where?" whispered Chow into his suit transiphone, startled.

"He means himself, cowpoke," Bud replied.

Tom planted an American flag, kept upright and in position by a small gravitex stabilizer, and saluted it proudly. "We aren’t legally entitled to claim Mars for the U.S.A.—but it’s sure a wonderful thing to think we made it here first!"

"Not counting the Martians," added Hank Sterling with a chuckle.

"Yeah," Bud put in. "Or those Planet X scientists."

"Yet I am also here, on behalf of my country," Dr. Yun declared. "And so, perhaps we might say that I stand for that small portion of the human race that happens not to be American."

Tom nodded. "As far as I’m concerned, that flag stands for science and the quest for knowledge—and knowledge belongs to every-one."

Tom’s sentiment raised smiles. Yet as the crew gazed about, they were unable to shake the eerie feeling that had descended upon them even as Mod 2 had descended upon Mars. As they looked out at the flat plains, broken here and there by rocky crags and ancient craters, it seemed to the visitors that the plains of Mars were looking back.

Knowing that they had only hours before sundown plunged them into frigid night, they quickly began to unload the special equipment that would give their exterior encampment a comfortable earthlike environment in which to work. This involved erecting the odd-looking device that Tom had first invented for use on Earth’s tiny second moon Nestria. Simply called an atmosphere-making machine, the atmos-maker would use an atomic furnace to extract breathable oxygen and nitrogen from surface materials, its whirling spreader jetting the mixed gases out into a pressure dome of the same suspended Inertite filaments as were used to cover the hatchway.

"Let’s give the dome an 80-foot diameter overlapping the hatch," Tom directed. "That’ll be plenty of room for us, I think."

"Say, boss, we gonna give this here camp a name?" inquired Chow. "Cain’t jest leave it as a dot on th’ map."

"Got one in mind?"

"Naw, wouldn’t be fair t’ give me the job," the ex-Texan responded. "I got to name the last one, when we ’as at the South Pole. Someb’dy else kin take a crack at it."

"Then I have a suggestion," Neil MacColter spoke up. "I grew up reading the Mars stories written by Edgar Rice Burroughs. Let’s use his name for Mars and call the camp Barsoom Base."

"Done!" Tom pronounced, pleased by the notion of honoring a great imaginative writer who, Tom knew, had inspired many a dreamer. "By the way, Burroughs has a big crater named after him, near the southern icecap."

Looking like a construct of cubical blocks, the base unit of the atmos-maker was assembled some thirty feet from the hatchway. At the touch of a button the disklike air-spreader rose to a medium height above the unit and began to whirl, not only emitting air but also spinning out the Inertite filaments that would coalesce into the permeable dome-enclosure, which was necessary to maintain pressure.

"Won’t be long now," commented Bud to his pal.

"Right," Tom nodded. "But keep your suit on, Bud. I’d like to take some soil readings about fifty yards beyond the dome, to see if we can find a better mix of soil to feed the air machine. There’re plenty of oxide compounds all over this rusty red planet, but I don’t want the nitrogen component at too low a proportion."

Soon Tom pulled open his helmet and announced that a comfortable shirtsleeve envi-ronment had been attained inside the airdome. The team began pulling off and stowing their bulky pressure suits.

"Hey," said Bud, "what’s with Tex Winkler over there?"

Chow was approaching Tom and Bud with a determined step. He was still wearing his Swift Enterprises spacesuit; in fact, he was pulling his bubble-helmet over his bald head, to reseal it to his neck ring.

In response to Tom’s question, the cook said, "Afore we shut down fer the night, I had a notion t’ try somethin’ out there in the open." He gestured toward the relatively flat ground beyond the dome perimeter. "I figger since gravity up here is only about a third, I orta be able to run three times as fast—jest like a pony!"

"Well actually..." Tom began. But the big cook held up a big hand.

"Now don’t you discourage me, son. Mebbe it won’t work, but I’m bound n’ determined to give ’er a Texas try." Chow stalked away, sealing his helmet as he approached the barely-visible curve of the filament barrier.

Suddenly Tom exclaimed, "He’s not bracing himself! Chow!"

"He can’t hear you!" muttered Bud. "He’s sealed in!" Starting to run, the youths pulled their helmets shut to activate their suit transiphones.

Chow strode forward confidently, stepping through the permeable dome—but only part way. Before he could penetrate the barrier further than one boot and the prow of his stomach, a strange invisible force seemed to seize him from behind. The big bulky westerner shot forward through the dome barrier like a human cannonball!

"He’ll be hurt!" Tom cried as he and Bud sprinted after Chow. And some very sprightly sprinting was required—Chow was tumbling and bouncing across the sands of Mars like a runaway whirlwind!

"Chow!" Bud cried into his transiphone. "Are you okay?"

The cook’s hundred-yard skid had sputtered to a stop. He lay face down, his bright red spacesuit streaked with dust. To the boys’ relief, he stirred at sat up.

A groan came across Chow’s transiphone—and then a few more pointed comments. "Bling blang dang!—if’n this here suit wasn’t made outa shock absorbers all the way through, I’d be nothin’ but a pile o’ bruises!" As Tom and Bud trotted up close and helped their friend to his feet, Chow made clear that he was far from placated. He glared at Bud. "Well, Buddy Boy, go ahaid ’n laugh!"

"Huh? What do you—"

"Come on, I know’d it was you—you an’ yer jokin’. You sneaked up behind me and gave me some kinda super-scientific push! What’d you use, one o’ them repelly-trons?"

As Bud started to bark out a denial, Tom said calmly, "Pardner, Bud never got anywhere near you. You just forgot about the pressure differ-ential, that’s all."

Chow frowned. "Fergot? Jest how could I fergit somethin’ I didn’t know about it in the first place? Tell me that, young’n!"

Tom tried to speak in soothing tones, not wanting to make the older man feel embarrassed. "It was part of your training, but I know these things can be easy to forget. The pressure inside the airdome is like Earth’s—more than ten times what it is outside the barrier. When the front part of you goes through the dome surface, there’s so little pressure on that side—"

"Uh-huh, right," said Chow, reddening. "The pressure on my big backside was enough to shoot me right out like a blame bullet from a sixgun! Sorry there, Bud."

Bud nodded with a smile, and Tom said, "Why don’t you try your experiment tomorrow, Chow."

"Right. Gotta give my aches n’ bruises a chance to settle in fer the night."

Tom and Bud turned to go back inside the dome for the equipment they would need, expecting Chow to follow. But instead—

Instead of walking after the two, Chow was still standing in place where they’d left him, slightly sagging at the knees. "Cain’t lift my legs!" he cried. "I’ve done gone all weak-like!"

Tom drew closer—then grinned. "Don’t worry. It’s just the gravitex unit built into your suit. Look at the dial. It must have got turned up high by accident, while you were imitating a billiard ball."

Turning down the power with a clumsy movement, Chow shot another bad-weather glare Bud Barclay’s way. "Accident, hmm. That it? Or is this jest mebbe this’n’s latest idea o’ makin’ fun o’ my husky Texas weight!"

"Now look Chow," gritted Bud, "you can’t blame me for everything that happens to you. I’m trying to turn over a new leaf—I, mm, sort’ve promised Tom."

Chow snorted but seemed to accept Bud’s account. "Okay then. Mebbe I’m jest in a mood."

Again he started to walk back to camp. And again, he couldn’t manage it! He swayed awk-wardly back and forth as if his feet were glued to the ground. "Doggone it, now what’d you do, Barclay-Bud? Boss—I can’t pry up my feet! They’ve sprung roots!"

Tom sighed. "It’s the ground-gripper filaments on the soles of your boots. You’ve got them on maximum extension."

"I do?" Chow looked at a small meter dial on his sleeve. "Hunh. Reckon I do. Sorry-twice, Buddy Boy." Adjusting the suit controls, the cowpoke picked up one foot tentatively, then the other. With a red-faced nod, he stomped back toward the airdome.

Tom shot Bud a suspicious glance. The dark-haired youth shrugged in reply. "Nothin’ to do with it, genius boy."

The two collected their test equipment and walked a little distance away from the airdome. Not far ahead the ground became noticeably rougher and assumed a downslope. One mile further lay the deep Coprates Chasma.

Tom knelt down and began selecting pebbles to be placed under the input sensor of his portable spectroscanner.

"Say Tom—what’s that sound?"

"Just the wind, I guess. It’s not like the moon, you know. There’s an atmosphere here."

"I know," Bud murmured. "But it seems kinda loud, don’t you—" He broke off with a gasp. "Tom! Look!"

The young inventor twisted his head around to look and echoed his pal’s startled gasp. Weird streaks of pinkish haze were drifting across the pale Martian sky. "That’s high altitude dust!" Tom exclaimed. "A windstorm!"

"Will it hurt the camp?"

"Bud—it could bury the camp!"

The next instant the full force of the windstorm swept across the camp like the blow of a hammer!

THE ONSLAUGHT of high-velocity wind rocked Bud and Tom onto their backs and started to drag them across the yielding surface. "Turn the gravitex up!" Tom shouted. "Max setting!"

Bud followed Tom’s example. Instantly the tiny gravity-concentrators in their suits forced them down flat against the ground, immobile, as the raging dust-laden winds roared over them.

Tom carefully turned up on one shoulder to see what was happening at the encampment. The airdome bubble, made visible by the reddish dust as it settled, was twisting out of shape like taffy!

"The wind’s gonna push it flat!" Bud choked.

"Not the wind," Tom muttered fearfully; "the particles in the wind. They’re big enough to force the filaments aside, and the dome barrier can’t handle it." The airdome would reconstitute itself after the storm had passed, Tom knew. But there was a real danger nevertheless. At the "kinks" in the deformed curvature of the barrier, the net of filaments would become so porous that the air would begin jetting out faster than the atmos-maker could supply it. "They’re not wearing spacesuits in there! If the pressure drops too quickly—"

"No, look—they’re all making for the ship!" Bud exclaimed in relief. The shirtsleeved crew was scrambling into the hatchway. As the last of them disappeared, the massive hatch swung shut.

"Thank goodness," Tom breathed—and then his breath caught in his throat as another panicked figure appeared around the far side of the atmos-maker’s base unit. "It’s Dr. Yun!"

"It’ll be okay, skipper," Bud reassured him. "The way he’s running he must still be able to breathe all right."

The two watched as Yun ran up the rampway to the closed hatch and vigorously thumbed the control button next to it. Nothing happened! "Something’s wrong!" Tom transiphoned over the shrieking wind. "We’ve got to help him!"

Decreasing their gravitexes Tom and Bud staggered to their feet and threw themselves into the teeth of the Martian tornado. It was one step back for every three forward. Yet they finally managed to force themselves into the quivering dome, where the winds were largely blocked.

Tom was horrified to see that Dr. Yun had collapsed on the hatchway ramp. As the pressure within the dome dropped, he was slowly asphyxiating! Tom and Bud were shouting into their transiphones already, and in a moment were pounding on the hatch panel.

"They can’t hear us!" Bud groaned. Then he turned and sputtered, "Tom! What are you doing?"

Kneeling down the young inventor had pulled loose his bubble-helmet, having touched the control that turned its engineered composition from something rigid as glass to something flexible and easily folded. Holding his breath, he compressed and twisted the material into a funnel-shape and pressed it to Yun’s lips, as tightly as possible. The man’s eyelids flickered gratefully as he drew upon the oxygen still coursing through the micro-capillaries within the transparent material.

Bud and Tom alternated applying their lifegiving oxygen, desperate to keep themselves alive as well as the Korean. But how long can we keep it up? Tom wondered. His head was swimming!

Suddenly he heard Bud gasp, "It’s—it’s letting up!" In a matter of seconds the great storm had rumbled along, charging off toward the cliffs of the Chasma, trailing skirts of dust.

The air pressure was rapidly restored, leaving three stricken astronauts gasping—but alive.

A clank announced the opening of the hatch. "Oh no!" cried Hank Sterling. "Someone—over here!"

Inside Mod 2 the three recovered quickly.

"We thought Dr. Yun had gone into his cabin," explained Marlene Jencks apologetically. "The door-hatch of his cabin was shut."

"It was a terrible nightmare," murmured Dr. Yun. "I could not imagine what to do when the hull hatch refused to open for me. All I could do was keep pushing the button."

"Bad time for a glitch to show up," Tom remarked.

"You preserved my life, Tom, and I am grateful. Just seeing you two out there, struggling against the winds—you gave me hope."

Tom smiled and said, "What I want to do now is take a look at that hatch problem."

The young inventor went outside and thumbed the hatch control button curiously. To his surprise the mechanism now responded imme-diately.

"Hunh!" Chow snorted. "Now jest whattaya make o’ that, boss?"

As Tom shrugged, Rafael Franzenberg responded. "Temporary effect of static electricity in the air—from the wind. Couldn’t be any dryer, you know."

"If you’re saying Doc Yun was a victim of a terminal case of static cling—man!" There was a good dose of skepticism behind Bud’s quip.

"It’s plausible, though," Tom stated thoughtfully. "We ran complete diagnostics right after landing."

Chow’s big eyes were narrowed. "Wa-aal, what I say is—they’s coincer-dence—an’ then mebbe somethin’ else."

Tom knew Chow was thinking of the strange, unexplained attacks back on Earth. Bud shot the Texan a wry look and said, "Don’t look at me, wrangler-man. I didn’t make the wind blow!"

The sun was setting at the bottom of a sky already crimson from a haze of fine dust. "Let’s switch off the heat lamps and batten down for the night," Tom ordered. "It’s about to turn into mid-winter in Antarctica out there."

"Do you plan to begin the rescue search tomorrow, Mr. Swift?—that is, Tom?" inquired Gretl Dornis, an older woman who was Enterprises’ chief biochemist.

"I’ll assign tasks tomorrow morning. But you can count on getting started looking for signs of life, Gretl. I’m anxious to get hot on the trail of Great-Grandad’s Martians."

When Tom made his end-of-day report to his father, he handed the PER unit to Dr. Yun at the man’s polite but insistent gesture. "Please do inform my colleagues in Korea that all is well here, if you would, Mr. Swift."

"Of course," replied Damon Swift. "Inci-dentally, I have our staff medic Dr. Simpson here with me. I thought he might ask you a few questions, Dr. Yun. We must do what we can to make certain there will be no consequences to your experience today."

"Very well," said Yun, somewhat reluctant. "No doubt it is advisable."

Young Doc Simpson was a close friend to Tom and Bud, and a medical researcher as well as an MD. "I knew I should have gone along on the trip!" he joked. Simpson asked a number of questions and had Tom use some instruments from the ship’s medical kit to perform a cursory examination. "Well, no obvious signs of difficulty from your temporary asphyxia, Dr. Yun," the doctor pronounced. "Tom, it’s mighty lucky you and Bud were using the old-model suits instead of the new ones you’ll be testing out."

"That’s for sure!" Tom agreed before signing off.

As they strolled back to the main deck area, Yun asked Tom to explain Doc’s remark. "As a late addition to your crew, I do not know certain details. There are two kinds of protective suit?"

"Yes," Tom confirmed. "Our standard suits have the kind of tanked oxygen-feed system that allowed us to help you, but the new experimental ones work on an entirely different principle." He briefly explained that the new exploration suits permitted greatly extended surface treks without the need to recharge the compressed air reservoirs. "Matter of fact, there are no external air feeds at all!"

"Ah? But how is this possible?"

"Get ready, Doctor—it sounds a little gruesome!" Bud warned humorously.

Tom chuckled. "Basically, the suit infuses oxygen directly into the bloodstream of the wearer!"

"My word! An intravenous connection?"

"Yes and no," was the reply. "There’s no measurable break in the skin. Virtually the entire inner surface of the suit—which would cover a surprisingly large number of square feet if you spread it out flat—is equipped with densely-packed microfeed tubules, barely visible to the unaided eye. As they press snugly against the skin they release tiny doses of a special solution that carries dissolved oxygen right through the epidermis and into the outer subdermal arteries, which are extensive."

Yun broke into a broad smile. "Indeed, I see now! I once wore what is called a nicotine patch. The principle is similar."

"Yeah," Bud confirmed. "Just think of it as a whole-body patch."

Tom added that a special medication originally developed by Doc Simpson was included in the oxygen-bearing solution. "It greatly increases the efficiency of respiration and suppresses loss of water from bodily tissues, as well as the, er, normal buildup of waste products."

"Which is mighty nice!" called out Chow from across the deck. "They’s sure no service stations handy up here on Mars!"

Yun asked how long an explorer could remain outside in the suits. "For days!—in theory. They even carry liquified nourishment. But I don’t plan on shifts of more than six hours at a stretch. Bud and I will be testing the suits tomorrow."

As darkness fell, lush with countless stars and two hurtling moons that made the shadows dance, Chow served a dinner imaginatively cobbled together from Mod 2’s un-imaginative store of rations. "Leastways it’s better than what we usedta have t’ eat—all that frozen, de-hydro-flated stuff. Weren’t fit fer a prairie dog."

"But this is delicious, Charles," commented Marlene. Chow beamed.

As the crew chatted quietly and kept watch on the Martian night, Chow returned to the galley compartment to bring out a dessert.

The fireball lasted only an instant as built-in extinguisher devices put an end to it. But every member of the shocked, fearful crew had jolted up with the same thought. The fire had come from the galley!

Tom leapt to his feet, but Bud was already on his feet—and running! He burst into the galley through a veil of smoke. "Chow!" The rotund westerner was lying in a heap on the floor, his colorful shirt singed, his bald head blackened.

Bud dropped to his knees and Chow began to cough and wheeze. "Is he hurt badly?" called Hank from the doorway, standing next to Tom, whose face had turned pale with concern.

"I—I don’t know," Bud whispered hoarsely. "But he’s alive!"

"I th-think my ol’ hide’s got itself smoked right good," groaned Chow weakly. "Th’ oven door took th’ worst of it, thanks be."

As Tom wrapped on soothing, healing-assist medicated bandages, he asked softly, "Pard, do you know what happened?"

"N-not exactly, son," was the shaky response. "I jest remember—I opened th’ oven, and—"

"There’s a little scrap of metal foil inside," Hank observed. "It’s charred black. Must have caused a microwave hotspot that turned into a fireball when Chow cracked the door."

Tom nodded. "Uh-huh. Fed by the high proportion of oxygen in the Mod’s air."

Bud would have none of it. "No—it can’t be just a coincidence—not again! One a day is my limit, guys."

"It’s dang pee-culiar," Chow chimed in, his tones even gravelier than usual. "Where’d that there foil come from? It shor wudden there a half-hour ago!"

"I know what it means, Chow, and so do you—Tom too!" Bud walked up to his pal and spoke fiercely. "Somehow or other, whatever was after those scientists on Earth has followed Dr. Yun to Mars!"

"WHAT’S Bud talking about?" demanded Hank Sterling. "What followed us to Mars?"

Bud could tell that Tom was half-ashamed of himself for having kept matters from the rest of the crew, trusted friends and colleagues from Swift Enterprises. "I’d hoped I wouldn’t need to dump it on everybody’s plate until the expedition was over, but now—I guess it’s time for a briefing."

Tom called the team together, explaining the situation with the assistance of Dr. Yun. "I’d assumed nothing about the incident with the door hatch," declared the Korean researcher. "And yet, perhaps there is something to what Bud Barclay has concluded, however rashly."

"All right, but look here, Doctor," huffed Franzenberg. "If someone deliberately set up a booby-trap, it was aimed at Chow, not you."

"Why would anybody do that?" exclaimed Neil.

"Thank you!" said Chow.

Tom’s frown was deep and bewildered. "What I’m afraid of is that—if these incidents were deliberate—someone has decided to target everyone on this expedition."

"Sure," grated Bud; "someone. How about if we jettison all the secrecy and careful talk and say it outright? ‘Someone’ has to mean someone here in this room right now—one of us!"

Tom shook his head, but it was a head-shake of reluctance—very pained agreement. "Bud’s right. There’s no place for a stowaway to hide. It might be possible, barely, on the Starward, but not in this little module. And the galley door is right over there in front of us, in plain sight. No stranger could have sneaked across the deck in front of our noses."

"Then as far as this physicist is concerned, it was just coincidence, some sort of fluke." Rafe Franzenberg stood up. "It can’t have been caused by anyone, because there’s no one to cause it. That’s the rational conclusion, boys and girls."

Chow scratched his head-bandage, which brought a wince. "Reckon I can’t argue with that."

Tom gave a smile that was unconvinced and a bit sour. "Well then, now that the matter is resolved—nothing to do but hit the sack."

Sleep was difficult. After a few hours Tom got up and wandered restlessly out to the main deck, where he found Chow pacing, a big wide silhouette in front of the huge curving viewpane and the somber landscape beyond. "Cain’t get a wink o’ sleep," grumbled the cook.

"Your burns aching?"

Chow shook his head. "Naw. Them special bandages help right nice. Jest got m’self in a state, worryin’. Ever’ time I hear a little tick ’r tack out here, I think it’s somebody sneakin’ up on us."

"It’s just our equipment switching from one programmed task to another," responding Tom, a hand on the westerner’s shoulder. "Think of it as a troop of automatic guards watching out for us."

"Okay. I’ll think it. And stick in some good earplugs!"

The expedition’s first Martian morning came suddenly, a wedge of the sun peeping over the horizon like a high-powered searchlight. "Mighty cold out there," said Neil MacColter to the breakfasting team. He pointed out the viewport. A layer of frost had collected on the inner surface of the airdome barrier!

"We’ll have to crunch it aside when we go out," commented Hank. "Minor drawback to having moist air to breathe."

Tom began to parcel out the day’s work assignments. "I’d like you two to set up the automatic telesampler station next to the cliffs," he said, indicating Hank Sterling and Dick Folsom, who was an expert electronics technician. "Chow—"

"Aw, I know, Tom," interrupted Chow with a wry snort. "You want me t’be the one who stays here in th’ rocket ship, doncha."

The young inventor grinned. "Just for today, pard—it’ll give you some extra time to heal up ‘right nice’."

He asked Gretl Dornis to work with Dr. Yun on the search for traces of Martian life, past or present. "You both have a biology background," he noted. "Dr. Yun’s field is cellular biochemistry." Tom put Neil MacColter with Marlene, who would be doing meteorological studies, and Lori Matthews with Dr. Fran-zenberg. "Bud and I will be testing out the exploration suits and the air scout," Tom concluded. "We’ll run the rim of the canyon first, then head inland to the north."

As the expeditioners broke up to prepare, Tom quietly pulled Rafael Franzenberg aside. "Maybe it’s just my imagination, Rafe, but—when I announced the team-ups, I noticed that Lori looked... well, a little disconcerted."

"My reputation precedes me, chief," declared the big, imposing physicist, who was never caught short on self-confidence. "As you know, certain women find me irresistible. Which has consequences, alas."

Tom knew very well that Franzenberg did, indeed, have something of a reputation! "I suppose, as head of the mission, I should ask—has anything happened between the two of you that might constitute a problem in working together?"

"Not a problem for me," he harrumphed. "As to the women, ask ’em."

"Women?"

"I believe in dating widely. One must have a broad sampling domain to acquire sufficient data upon which to base justifiable conclusions. Science is founded on evidence, and evidence is derived from experience. Wouldn’t you agree?"

"You were involved with Marlene as well as Lori?"

"And Gretl." Rafael gave a wide and knowing grin.

Unsure how to react, Tom ended up looking amazed. "All three?"

"No, no, not at the same time, of course. I carefully spaced them out on a daily schedule throughout the week, without overlaps or crowding. Whole thing didn’t last more than, oh, four months or so. With an occasional hiatus for recuperation."

"I see."

The physicist shrugged. "Naw you don’t—not at your age, kid. But I’ll tell you something about the firmer—I mean, finer—sex. They don’t like the process of alternate comparison. Makes ’em jealous. You noticed Lori’s face, but the other two made even worse faces, let me tell you. I was watching. Pure animal jealousy and pos-sessiveness."

"Well," Tom said, "I expect all of you to do your jobs in a professional manner."

"Don’t fret, chief. They’re all good gals—that’s why I turned on the charm to begin with." As Tom nodded, Franzenberg added: "I don’t anticipate any hair pulling, not at this point."

As the teams prepared for the day, Tom and Bud made their own preparations, which consisted in suiting up in the new experimental suits. The garments were thickly padded and a gaudy green in color for easier long-range visibility. The flexi-helmets were similar to those of the standard Enterprises spacesuits—fishbowl-like globes that could be folded back like sweatshirt hoods—but Tom explained that the inbuilt helmet air-feed system would only be used to maintain the pressure balance in the wearer’s lungs with a moist nitrogen-helium mixture.

"These suits are oversize-plus. I just hope we’ll fit inside that flying compact car of yours," Bud declared ruefully.

Tom laughed. "We’ll go sporty and put the top down!"

The maglev flyer, as Tom called it, was removed by crane from its cradle in Mod 2’s hold. It was a sleek, wheelless vehicle, only about eight feet from stem to stern, equipped with a wraparound windshield. "You say your Mars Special works by magnetism?" Bud inquired.

"Magnetic levitation," was the reply, "already in use on some of those high-tech bullet trains. Extremely powerful electromagnetic flux coils running along the underside induce a magnetic field in the ferrous—this is, iron-bearing—granules in the soil. The induced magnetic currents push back against the field that created them, which produces a lift effect."

"Very high?"

"No, flyboy," Tom said. "Just a few feet—and we can only get that much altitude in a lower-gravity environment like that of Mars." He noted that the high iron content of the Martian soil was crucial to the operation of the flyer. "It really is a Mars Special. It wouldn’t work back home."

The youths climbed aboard. "Maybe Swift Construction can sell ’em to Martian com-muters," Bud cracked. "But what makes the thing move forward?"

Tom gestured toward the rear with his thumb. "That parabolic dish mounted back there is a small repelatron radiator. Even though single repelatron field-beams are too unstable near the planetary surface to provide constant vertical thrust—which is why we can’t just use the Repelatron Donkeys for near-ground explo-ration—we can still get some good horizontal thrust by aiming it off in the distance, toward the horizon."

"Okay, enough explanations. Let’s go explore Mars!" chortled Tom’s pal.

Tom activated the flyer’s neutronamo power source and cautiously worked the controls. The craft bounded upward like a soap bubble to a height of nearly five feet. "Wow! Better than expected," Tom murmured happily.

"Hey, look at that!" cried Dick Folsom from across the campsite. The other team members waved goodbye and good luck as the flyer accelerated forward and passed easily through the Inertite barrier, from which the film of frost had already melted. Its gravitex devices braced the Mars Special against the jolt of the pressure differential.

"Jetz! This is great!" Bud exclaimed.

Determined to put his new invention to the test, Tom opened her up, metering power to the repelatron. The craft shot forward, executing some smart turns with the aid of the inbuilt gyros and gravitex stabilizers.

The young space commander turned the nose of the flyer toward the cliffs that edged Coprates Chasma. Soon they were speeding along east-ward, a few yards inland from the ragged edge but well able to see into the depths of the huge canyon-like fissure, far larger and deeper than Earth’s grandest Grand Canyon. Though in some areas they could see gentle slopes and what looked like ancient landslips, a good part of the Chasma walls consisted of jagged upthrust rock and a tumbled terrain, wildly uneven. Bud muttered, "How are we ever going to find the Red Eye guys, if they ended up somewhere down there in the middle of all that?" He glanced at his friend. "Can the Mars Special even work down there, with the ground so jutty?"

Tom shook his head. "It’s only designed for use on the level plains."

"You mean we have to explore that big crack on foot—in just a couple weeks?"

"I know it seems hopeless, Bud," Tom said, the hollow Martian wind whipping by with barely a whisper. "As I explained to Dr. Yun and the ENCOSS delegation from Korea, our main chance lies in the possibility that the survivors might transmit another signal, which we could follow to its source. Other than that, about all we can do is comb the area with our instruments. It’s possible that something might be visible down inside the Chasma, in plain sight. The rugged terrain interferes with the megascope beam, so our earlier look-see from Earth wasn’t the final word." Tom noted that the limitation on the electronic space prober was one reason he still held out hope that his great-grandfather’s dramatic evidence of a civilization on Mars might yet be discovered.

They flew along, eyes and instruments operating with peak efficiency. "Plenty of shadows and fissures down there," observed Tom. "And it’s even worse a ways to the west, where Coprates joins up to the Valles Marineris proper. You could drop the state of Connecticut in there and never find it! If they came down in there, it’d be years before we’d be likely to run across them."

"Unless they send a signal," Bud reminded him.

Their odyssey took them more than two hundred miles away from Barsoom Base. Finally Tom turned about. "We’ll take a more inland route on the return leg. Maybe we’ll happen across something in the Ophir desert."

Soon they found themselves whizzing over a vast, rock-strewn plain stretching from horizon to horizon. "This is what I call dull scenery," Bud complained. "If it weren’t for the craters, it’d be nothing but basic flat." He nudged his pal. "If this is the tourist package, I want my money back!"

Tom chuckled. "No monsters yet. But the craters are pretty interesting in themselves, chum. They show how old the surface is. Mars has been bombarded by all manner of meteors and asteroids for billions of—"

The young inventor broke off, and Bud turned to regard him curiously. "See something?"

Hands on the controls, Tom gestured with his chin. A plume of dust was rising from the horizon in front of them. "Another windstorm?"

"No, I don’t think so," Tom replied, puzzled. "I suppose it could be what they call a dust devil, a sort of desert cyclone. But..."

Bud was turning wary. "No ‘buts,’ pal. Let’s enjoy it from a distance."

Tom turned the nose of the maglev flyer back toward the Coprates Chasma, which now was out of sight beyond the horizon. But it made no difference. Within a minute they were alarmed to see more of the mysterious streamers of dust, this time toward the south ahead of them. "Good night!" Bud gulped. "Something’s kicking up the dust all around us!" A rolling red haze seemed to be charging the craft from every horizon. They were boxed in!

Tom came to a sudden dismaying realization. "It’s a quake! The ground is shaking dust particles into the air!"

"Can’t we backtrack?"

"Backtrack where? The quake sectors are spreading—we’re right in the middle!" Never-theless Tom gunned the repelatron and desperately put on the speed, aiming at an area where the dust seemed somewhat thinner. He knew—and Bud sensed—that if the rippling of the ground overtook the flyer, the unevenness of the surface could interfere with the maglev reaction. They could crash!

But then the nightmare redoubled. As the dust engulfed them, the ground heaved up in two directions, opening up a broad fissure directly in their line of flight. Almost before the youths could think, the Mars Special had plunged over the edge—into darkness!

BUD BARCLAY was made of equal parts courage and excitability, and in this extremity it was the emotion that won out. He yelped in fear, grasping his restraining shoulder straps, as the sunlight was whisked away behind them.

Tom Swift was able to tap his reservoir of calm. He worked the cybertron mini-control unit in his hand, trying to maintain some measure of stability for the stricken craft.

The Mars Special had lunged in an instant from the dust-dimmed sunlight falling into the mouth of the crevice, into blackness. The thin Martian air carried a thunderous roaring and crashing to their ears—the grumbling groan of Planet Mars!

The dizzying fall seemed faster than it was. But even at one-third the pull of Earth, the astronauts knew that unyielding rock walls—and a catastrophic crash—were close at hand. Tom allowed the flyer’s cybertron guidance system to radar-detect the contours of the open space around them, steering by means of the stern-mounted repelatron. But now the instability effect had taken over. The repelatron’s force ray was unable to tune itself precisely to the detailed composition of the nearby walls flashing past them. The Mars Special swerved and vibrated erratically as it descended, sideswiping the rocks with enough force to hurl Tom and Bud out into space! Only their taut safety straps held them in place.

Tom managed to switch on the flyer’s headlamps. To his surprise, the long beams barely reached the edges of the great chasm into which they had fallen.

"We must be in some kind of volcanic shaft or eroded-out lava pipe," murmured the young inventor. Bud shot him a sardonic look. At the moment, scientific observation was not a pri-ority!

Tom used the stabilizers to reorient the craft as it fell, angling its nose upward and the repelatron downward in the direction of motion. Instantly the youths were pressed back in their seats as the repulsion counterforce took hold, slowing the descent.

"M-maybe you can push us all the way back up," Bud gasped.

"The field-beam is too scattered and unstable," replied his pal grimly. "I can’t get a fix on anything. At least it’s slowing us."

With the computerized assist of the cybertron, Tom attempted to balance on the repelatron beam as if on stilts. The flyer no longer whanged against the sides of the shaft, though falling rocks whanged against them. "Good grief, doesn’t this ever end?" demanded Bud in a shaky voice. "Is Mars hollow?"

"We’re not all that deep," said Tom quietly. "Less than two miles down, I’d say. The radarscope is getting some bounceback from a bottom."

"How far below?"

"A few hundred yards. But it’s sharply slanted and very uneven."

In fact, the vertical shaft was beginning to shift toward the horizontal. Using the repelatron Tom forced the flyer into a sideways trajectory as the downsloping floor loomed near.

"We’re slowing down," Bud declared.

"The maglev coils are starting to get some bite, now that we have a surface close under us. If the slope gets shallow enough, I should be able to brake us."

Finally the headlamps revealed a broad, low-ceilinged cave, the overall slope of the floor no steeper than a modest hillside. Tom decelerated the craft—and cried out in alarm as it suddenly swerved sideways toward a hanging curtain of stone.

"Duck down!" he yelled, yanking on Bud’s spacesuit sleeve. Releasing their safety straps, they hunkered down as best they could. There came a violent, screeching shock—another—and the Mars Special suddenly crunched to a halt, half turned on its side.

Tom and Bud were catapulted forward from the cockpit, slamming against jagged rock which shattered in all directions like a thin pasteboard crust.

Lying still at last, Tom moaned. Bud replied with a faint: "Chow was right—thank goodness for padding!"

Though the flyer’s lamps were still shining, the boys had fallen into the opaque shadows behind the thin rock overhang. They switched on their small suit lamps, staggering to their feet, trying to maintain balance on the wildly irregular surface. "Check the readouts, Bud. Any sign of leaks?"

"Pressure’s steady," replied the young pilot. "As to my pulse rate—different story."

"Yeah. Quite a ride!"

The two turned about, throwing the lamp beams in different directions. "This little mini-cave doesn’t lead anywhere," Bud pronounced.

Tom nodded. "Just an old petrified lava bubble blown out from the main shaft. Let’s go back to the flyer."

Falling to their knees, and eventually to their chests, they crawled and squirmed their way under the rock-curtain and stood up next to the Mars Special. Tom groaned in dismay. "Great space, what we have here is a wreck."

"Uh-huh. ‘Houston, we’ve got a problem!’ Yeow!"

For all the high-tech strength of its composite shell, Tom’s maglev flyer was in sad shape. Though there were no breaks in the hull, it was easy to see that the undergirding frame was twisted, and some of the Tomaquartz cockpit panes were almost pried loose from their positioning flanges, barely hanging in place. Worst of all, the Lunite antenna rod in the repelatron radiator dish had snapped in two, rendering useless that crucial propulsion element.

Tom climbed aboard, setting the craft to rocking back and forth, and checked the instruments. Then he awkwardly clambered out onto the rocks and popped open the repair access panel. He whistled in dismay. "Good grief! Here’s a good example of why you should always follow the instructions in the manual! By using the coils to brake us as I did, I caused a back-reaction, a super short-circuit. The circuitry looks like somebody went over it with a blowtorch! The neutronamo’s in shutdown mode," he reported. "The flyer’s running on the battery reserves."

"Is that enough to make the lift coils work?" Bud asked bleakly. He feared the answer—and got it.

"No way."

"But—" The big dark-haired youth tossed his head and licked his dry lips. "You can rig up something. Right, genius boy? To get us back up topside?"

Tom slid down off the big jutting rock, plopping down on a shelf of stone next to his worried friend. "Same answer, pal. We’ve tumbled down the rabbit hole to Wonderland—the underlands of Mars, that is. If you want to hike back, I’d say it’s a good three miles. Thataway!"

He pointed—straight up!

"WE’LL find them," declared Hank Sterling. His voice held no hint of doubt. "Both of them—alive!"

"Aw, I know we will," responded Chow, trying to keep the gravel in his Texas voice from shaking loose. "But—"

"But what?"

"Brand my starry spurs, what if I’m wrong?"

"We must find them!" said Dr. Yun. "Not only for their sake, but for the sake of the Red Eye survivors."

Morning had become noon, afternoon had become late afternoon—with no sign of the maglev flyer, no radioed word from Tom and Bud. Hank, acting mission commander in his young employer’s absence, had finally organized several search teams who trekked over to high ground in several directions, seeking good vantage points from which to survey the landscape. Meanwhile, radar probing from Mod 2—and from the orbiting Starward, remotely accessed—showed nothing for hundreds of miles around.

As the sun drifted lower, Hank lifted off in the Excursion Module with her crew, leaving the self-sustaining airdome and atmos-maker behind, Gretl Dornis remaining in case the boys should return. They flew in an expanding spiral, high and low, even dipping down to skim the flat bottom of Coprates Chasma all the way to its junction with Valles Marineris. There was nothing to be seen, only the strange tumbled landscape of the bleak Red Planet.

"All this could have been easily avoided," huffed Rafael Franzenberg. "Tom could have brought along a second PER unit configured for communicating between the Mod and the flyer."

"True enough," said Hank. "Their radiocom is useless with a horizon or two in the way—not to mention ‘down in the valley, the valley so low’."

Chow snorted. "Ain’t no time t’ sing songs, Sterling."

"But that fact also gives us a bit of hope, doesn’t it?" Lori Matthews spoke up. "What if they ran across the Red Eye survivors? If they had been detained there, they wouldn’t be able to radio and tell us."

Yun nodded with a slight smile. "Ah, would that it were so."

At last, the sun a sliver, Neil MacColter piloted the ship back to Barsoom Base. "Nothing to report," Gretl reported.

A somber quiet fell over the main deck. What could have happened? A mishap with Tom’s new invention? A freak weather phenomenon? Could it be another case of sabotage?

Suddenly Hank slapped his head. "What a jerk I am!" he exclaimed. "There’s an easy way to find them!"

"Huh? Wa-aal don’t hold back fer th’ surprise, tell us!" demanded Chow.

"We just have to get in touch with Swift Enterprises."

"I’m afraid I don’t follow you, Hank," Gretl said.

"We can have Mr. Swift use the megascope to search the area!" laughed Hank in excitement. "It won’t reach down deep in the slope crevices, but it’ll give a better survey of the flat areas than we could manage with our naked eyes."

The crowd bustled over to the com-munications console behind Hank, and the young engineer slid the Enterprises-linked PER cartridge into its slot. But after a moment the others could see concern and irritation on his face.

"Sumpin wrong?" asked Chow.

"I’m not getting a connection. Nothing’s coming back."

"Try one of the other cartridges," Dick Folsom urged. Hank proceeded to try the cartridge attuned to the Swift home, then all the others.

The efforts were futile. "I can’t understand it," stated Hank. "The circuitry checks out just fine."

"Let me try it, Sterling," Rafe Franzenberg said curtly. But after several attempts the big physicist and electronics engineer was as baffled as his younger colleague.

"Perhaps the signal is being blocked in some way," suggested Yun Dai Koh. "Or—and I do hate to bring this up—perhaps it is being jammed intentionally."

Franzenberg responded with careless impatience. "That would be contrary to the laws of physics, Yun. The PER utilizes a quantum-entanglement principle. The spatial distance between the counterpart units is, in a strict scientific sense, zero. Which means, obviously, that nothing can come between them."

"Wa-aal, somethin’ shor has—obviously!" Chow put in sarcastically; "An’ I’d think you great brains wouldn’t have t’wait fer yer dang cook t’tell you what it is!"

"What do you mean?" Marlene inquired.

"It’s them Planet X people!—jest like t’when they stole the space station an’ moved ’er over t’ Venus!"

The never-seen X-ians, dominating superiors of the Space Friends based on Deimos, had used their advanced technology to a fantastic end, moving the Enterprises space outpost from Earth orbit to an orbit about the planet Venus. Tom had headed up a long and desperate rescue effort, bridging the millions of intervening miles with the help of his space solartron invention. Though the effort achieved its goal in an unexpected manner, no adequate explanation for the alien beings’ actions had yet been provided.

"What Chow’s talking about is this," Neil explained. "The spacemen created some kind of invisible ‘shield’ around the outpost that radio communications couldn’t get through. And he has a point. For all we know, something like that might pry apart the quantum link, too—whatever the laws of physics have to say about it."

"Right!" sniffed the culinary cowpoke.

"If that’s what we’re dealing with, we may be in more trouble than we realize," noted Hank with furrowed brow. "That same barrier was able to stop the Challenger from passing through it. I’ve been assuming that if worse came to worst we could rendezvous with the Starward and use the com system up there, or even hand-carry the specs of the problem back to Earth—it’s only a trip of a few hours, after all. But—"

"Let’s give it a try right now," declared Neil, striding over to the main controls. "With the boys out there somewhere we really don’t have time to fret over it." He closed and sealed the hatch and activated the repelatron bank. The big sphere stirred slightly—and then settled back down onto its landing struts. "No go!"

"But how can this be?" cried Dr. Yun. "Within the hour we were able to fly freely!"

"Sure. And within the day, we were able to get in touch with Swift Enterprises, too!" grated Hank Sterling. "For some reason, someone has decided to keep us isolated down here—marooned on Mars."

Chow gulped. "Sterlin’, that may have a nice ring to it, but right now it’s purt near last on my list o’ things I wanna hear!"

Dr. Yun rubbed his eyes despairingly. "I fear we must consider some further possibilities, my colleagues. If the aliens are willing to undertake such extreme measures, it may well be that they themselves caused the crash of the Red Eye. Indeed, the beacon signal may have been false, to lure us here to captivity!"

A gravel voice broke the startled silence. "Y’know thet list o’ mine, folks? I jest revised it!"

Even dismay and bewilderment could not stop supper. As the disconsolate crew sat about eating, Dr. Yun cleared his throat and said, "I must say—for we are in this same boat together, eh?—I have not revealed everything about myself and my interest in seeking survivors of the ENCOSS mission."

"Were you personally involved in the planning, Dr. Yun?" asked Lori.

"No, yet my stake is a very personal one. You see," he began, "I was a researcher at one of the Korean technology companies deeply involved in the scientific aspects of the project. My own particular specialization was experimental molecular genetics: we were trying to produce new medications by a cloning methodology, a common dream in those days, if you recall. Even now.

"As a minor consultant I had some occasional, inadvertent contact with the Red Eye people; and in this way I met the selected astronaut from my country, a most vivacious woman named Ri Quong-Ju. We had biology in common, one might say. To be frank, we found ourselves in love."

"Love ain’t easy," Chow opined in the voice of a wounded veteran.

"Easier for some than for others, especially at inconvenient times," was Franzenberg’s contri-bution, which seemed to draw ice-laden glares, oddly simultaneous, from the three women present.

"I cannot defend love, nor explain it," continued Yun. "In secret, we made plans to marry upon her return after nearly three long years. The night before the departure of the Red Eye, I gave her a little poem to take with her, near her heart. It said that I would climb the path of stars, however long, to be with her."

Chow sniffled and wiped his eyes with his cowboy bandana.

"This all must be incredibly difficult for you, Doctor," Hank said after a respectful moment. "I can see why finding the truth about the mission would be especially important to you."

The Korean nodded shyly. "Yes. And if I find nothing, I would almost like to remain here; for what then is life worth to me? But of course I have a duty to my country to return and report."

Later, in the dead of the Martian night, Hank was startled from a troubled sleep by a rap upon his compartment door. Lugging the heavy door hatch open, he found Marlene Jencks awaiting with wide eyes. "I got up to check one of my instruments, and I’m sure I saw someone outside the ship!"

"Outside! In the airdome?"

"Yes—someone skulking around in the shadows!"

They rushed to one of the Mod’s instrument panels. "It’s well below zero out there!" Hank hissed. "Is anyone missing from the ship?"

"I don’t know," replied Marlene doubtfully. "Shall I alert everyone?"

Hank shook his head. "No, I’ll suit up and check things out. You know—it could be Bud and Tom! The hatchway button might be acting up again."

Sterling pulled on his temperature-controlled spacesuit and exited the ship into the airdome, illuminated by the shifting gleam of the double moons of Mars. As Marlene watched anxiously through the viewpane, he began to make his way around the perimeter, looking behind the various piles of supplies and equipment.

Hank was on edge, and cautious. He felt vulnerable and unprotected beneath the night and stars of what was, after all, an alien world. Several times he gasped, startled, as he seemed to detect movement out of the corners of his eyes. It’s just the moonlight, he concluded ruefully. Those two little moons move pretty fast and the shadows are playing tricks on my eyes. But—hey..!

Marlene saw Hank bound across the clearing with triple-size strides toward the big high bulk of the atmosphere-making machine, disappearing from sight behind it. He didn’t reappear. The minutes ticked away, and sudden fear began to assault the nervously watching planetary mete-orologist.

"EVEN IF we could make our way back up that rocky ramp to where the cave branches off, we couldn’t climb up that vertical shaft," Bud stated grimly. He added with a twitch of grin: "I mean, I might be able to, genius boy, but your idea of a gym workout is lifting a screwdriver!"

His pal managed to squeeze out his own wan version of a smile. "Trying to go up is a good way not to get anywhere."

"Maybe you could repair the radiocom on the flyer."

Tom Swift shook his head inside his fishbowl helmet. "Bud, we’re three miles down and well over the horizon. Even if the com were working perfectly, the amount of iron-laced rock between us and Barsoom Base in cubic yards—"

"Don’t finish. I’m depressed enough."

They sat side by side in discouraged silence, for too long a time. At last Tom rose to his feet. "I guess down is the only way to go."

Bud also stood. "You mean, keep hiking down this cave? Won’t that just make us harder to find?—our bodies, that is!"

"It might work out, just possibly," replied the young inventor. "I’ve been thinking about the geophysical structure of this region of Mars. We’ve learned some things about it already. The big shaft and this cave are, basically, giant cracks in the ground—fractures. It’s turning out that quite a bit of the planet’s upper strata is—well, I guess you could call it foamy. The rock is super lightweight, full of gaps and emptied-out bubbles and pockets where hot gases must’ve collected when it was molten. Basically, everything has been hollowed-out. Look." He grasped a pale hand-sized rock jutting out from the cave wall and pulled it free. Clasping it firmly between his two gloved hands he easily snapped it in two in a spray of dust.

Bud marveled. "Good grief! The rock is brittle as sandstone—or old rotten wood!"

"A lot of it is. And I’m thinking this whole Ophir plain must be riddled with caves and fissures everywhere, all around us. The Mars quake just happened to cause a bit of the thin crust to collapse."

"Yeah—right in front of us," agreed the young flyer ruefully. "But I still don’t see how that’s a good thing, Tom. Even if we found another cave, who knows whether it’d end up even near the surface?"

Tom nodded. "You’re right, but I’m thinking of something else—the Coprates Chasma. We’re not really all that far away from it. There’s a good chance the process that first created it also created a network of fault-fissures radiating away from it, but connecting up to each other. Just by following the cave system in that general direction, we might finally pop out on the Chasma’s inner slope."

"Uh huh," said Bud skeptically. "And just how many days will these super-suits keep us alive?"

As Bud sank down again onto his rocky bench, Tom reached over and yanked his chum to his feet. "Keeping alive is tomorrow’s worry, Barclay. As for right now, I still live! And you and I are going to do whatever it takes to come out on top—like always."

Bud gave the best salute his helmet and padded glove would permit. "Then onward and downward!"

After preparing a note to attach to the cockpit seats that stated their plan, they left the wreck of the Mars Special behind, quickly losing it in the twists and turns of the down-slanting corridor of tortured stone. As the dull hours wore on their suit lamps revealed an unending panorama of dark rock-fingers, grasping and gesturing rudely at them on all sides, above and below. Sometimes the cave grew so broad that its further reaches were lost in dead shadow. Other times the sides seemed to crush together, and the youths could only proceed by shouldering aside the fragile, crumbling walls to make the opening as wide as a human body.

"Man, the rock is so crumbly, I’m surprised it doesn’t just fall in on us—especially what with the weight of everything above it," Bud observed.

"It’s worth study, all right," agreed his companion. "There must be a sort of under-girding ‘skeleton’ of stronger stuff. The fragile material just lines the caves and crevices."

They tried not to watch the clock. But when Tom finally called a halt to rest, he told Bud that they had been descending for nearly four hours. "How far down do you suppose we’ve got to?" asked Bud.

"Judging by my suit gauge, roughly another 3500 feet. Which is just fine; we’re not trying to set any depth records."

"But—how far have we gone in the direction of the big valley?"

"Can’t tell," Tom replied. "Miles, certainly. If the photon-deflection compass is accurate, most of our movement has been in the direction we want."

Unfortunately, another wearisome hour brought the news that the cave had now swerved away from the Chasma. "We’ll end up going in a circle!" groaned Bud. "What should we do?"

"Take a side cave. But..."

"I know—which one?" Suddenly the muscular young pilot gave a grin. "Want to flip a space wrench for it?" The two had let fate make its own decision on previous occasions.

Tom chuckled but shook his head. "Let’s suck up a little nourishment from the suit bags. Maybe something will come to us."

"Sure—a white rabbit for us to follow!"

Trudging along some time later, looking for who knows what, Bud suddenly yelled out, "Hey! What in th’—?" He bent over, looking down at his space boots. The left boot had sunk down into the crunchy floor nearly up to his ankle.

"Stuck?" asked Tom. "The ground’s been getting softer and flakier."

"Feels funny. I’ll pull myself out." But his foot didn’t come free easily, and when the youth gave an extra jerk, the force sent him stumbling forward down the cave slope, where he flopped over onto his stomach. Tom began to laugh at his friend’s predicament—but the laugh froze in his throat.

"You can’t get up?" cried Tom.

"N-no. Can’t get ahold of anything. It’s like—quicksand or something!"

Tom began to rush forward, stretching out an arm, but Bud warned him back. "You’ll sink in too—there’s a dropoff!"

"I’ll try over by the wall."

Tom edged along the wall, testing every step with dread and caution. Yet he forced himself to hurry. Most of big Bud Barclay had already disappeared from view!

Bracing himself, Tom reached out his arm. But strain as he would, he could come no closer to Bud’s fingertips than six inches. "Hey—got an idea!" Bud transiphoned. He explained, and Tom gave it a try. Like a human spider he walked up the side of the cave and, after finding a suitably firm spot, stood on the low ceiling, his head pointed down. From that position he could easily reach "up" to grasp Bud’s hand and carefully swing his pal free of the clutches of the Martian soil.

"Thank goodness for those gripper-soles," gulped Bud. "Forgot about ’em, hmm, old brain-bean? And you invented ’em!"

They looked at one another—and suddenly, unaccountably, broke out laughing! "Man oh man, if it isn’t one thing it’s another," chortled Tom helplessly. "But look at your spacesuit, chum." Bud looked down and noticed that much of the bright green was obscured by a darkish stain of some sort.

"What is that stuff?" he asked. "Another kind of dirt?"

Crouching down, Tom pulled a small object from one of his suit utility pockets. It looked like a rectangular piece of thick glass, about three inches high by five long, with a silver wire running around its edge. Holding the device up to his helmet in line with his eyes, he bent near Bud’s suit fabric and switched it on. A bright rectangle of light appeared on the fabric. "It’s my li’l ole prisma-visor," explained the young inventor, "an improvement on the self-illuminated magnifying glass I carry with me. It gives you a spectrum band in the middle of the visor pane, so you can get a crude preliminary analysis of the composition of whatever you’re looking at."

"You’re just full of inventions, aren’t you! So what is it?"

Tom frowned as he concentrated his attention. "Well... Let’s look at some of it from the source." He dug in with his hand and scooped out a bit of dark dirt from the cave floor. Examining it, he said at last: "Flyboy, it’s water—basically."

"Whatcha mean, basically?"

Tom stood, looking like he had an overpowering urge to rub his chin, or at least scratch his head. "It’s water in solid form."

Bud shot him a look. "I believe it’s called ice, pal."

"Yep. But it isn’t ice, not in the usual sense. You see, ice crystals can form in nine different configurations, most of which only show up in very unusual conditions—high pressure, mostly. It looks to me like this is one of the weird ones, which means it could have some properties you wouldn’t see in what we would call ‘ice’."

"Okay, but if it’s solid, how is it I sank down into it like that?" objected Bud.

Tom explained. He was excited by the thrill of a strange discovery! "The crystals aren’t joined together into a continuous sheet, but scattered throughout the soil in separated fragments, like dust. Evidently, mechanical pressure—like when we press down on the soil—causes them to momentarily liquify, creating a superfine ‘sludge’ that gives way like quicksand. I wonder what sort of geophysical phenomenon brought it into existence," Tom continued musingly. "Maybe some shock effect of the crater-making bombardments; or maybe it’s actually welling up in veins from a high-pressure area way down deep."

"Um, very intriguing," commented his fellow spaceman. "Maybe we’d better test the ground with our toes from here on."

After a long rest they proceeded again, cautiously, staying close to one side of the cave. "Hey, is it my old gray eyes," Bud spoke up suddenly, "or is the ground moving?"

The two halted and watched. The new phenomenon was uncanny! The midsection of the cave floor seemed to be trying to keep pace with the hikers, albeit very slowly. As the dull dry surface oozed along at a snail’s pace it formed ripples, like wrinkles of dirt. Tom examined a section. "Let’s keep walking. I think we’ll find another Martian surprise around the bend."

A few further twists brought the sight Tom had in mind. The suit lamp beams danced off something shiny that made wavery reflections on the ceiling. "A stream!" Bud exclaimed happily. "Looks like the ice finally melted."

Tom grinned but said, "Yes and no, pal. It’s an ice flow of our weirdo ice, sliding along a few thousand times faster than glacial ice likes to go on Earth, in spite of the lessened gravity. See, poke your hand in—it’s still solid."

"But it moves. Like syrup, but still..."

"The growing longitudinal pressure, from the growing weight of the ice vein further above it on the slope, is shattering and liquifying the individual crystal structures, giving them some freedom to move. But they recrystalize almost instantly."

Bud gave a shrug. "Can we drink it, skipper? Eventually we may have to."

"I don’t know," answered Tom. "We can’t drink it in solid form, that’s for sure. If we melted it at this point, we’d just get fine Martian mud."

"Oh well, at least the stream will keep us company," commented the other. "Hey, I might start whistling!"

They decided to camp there next to the ice stream for a few hours of welcome sleep. Then, their underground "night" behind them, they pushed on—and down, ever downward into the depths of the Red Planet.

Presently they entered a length of corridor in which the main cave seemed unable to decide on a direction. A number of cracks and sub-caves branched off hither and yon—even up into the ceiling and down into the floor. Bud looked at his pal and asked, "So where do we go?"

"We might as well follow our stream," was the answer. "It seems to be tending in the general direction of Coprates. And like you said, flyboy, the time may come when we’ll need the water."

The new cave was very different from the old one. It was unnervingly narrow, with high straight-sided walls, a ceiling too far above to make out, and a steep, rugged downslope for a floor. It was difficult for them to keep their feet. The boys had to pick their way along precariously next to the stream, which was showing traces of free liquid for the first time.

It was also becoming warmer. "The temp’s now over 40," Tom reported, checking his suit meter. "We know there’s active volcanism on Mars—maybe there’s a hot spot somewhere down below us."

When Tom glanced up, Bud was pointing silently into the distance, eyebrows raised. The young space explorer followed with his eyes, and whistled softly. In his suit lamp beam a hazy, fluttering plume, like an ostrich feather, was protruding from the wall!

"You’re not gonna tell me that’s the rear end of a Martian bird, are you?" inquired Bud, mystified.

"There are more further along—see?" Tom edged closer—then laughed softly. "Water vapor! It’s a mini-sized steam geyser."

"Funny we don’t see any water dribbling down from the cracks."

"There is, but it doesn’t last long enough to be noticed," explained Tom. "In the almost-no air pressure, the water is sublimating—turning directly to vapor without the liquid phase."

As they made their way along, the narrow cave began to fill with a puffy haze. "The atmospheric pressure’s gone up a little," Tom reported; "more than I expected. Something unusual’s going on."

"Well, there’s something unusual," Bud declared with a nod. A nearby section of cave wall was cloaked in some dark, rough substance that they had not seen before. It almost looked like velour cloth.

Tom examined it with his prismavisor device, and his voice became puzzled. "I don’t have a clue what this stuff is, Bud. Strange stuff! It’s made up of little curly flakes and twisted spikes." Looking even more closely, he continued: "You know, I think it has a fractal structure—the more general form is repeated in the smaller components, and over again in the yet smaller parts."

Bud asked, "But what is it? Some kind of mineral bed? Underground chemical deposits?"

Tom could only shake his head. "I’m not getting detailed-enough spectral readings to make a good guess."

As they continued, the purple-black material became ever more prominent. Eventually the cave walls were completely covered with it, and stiff "threads" of the mossy stuff were dangling down from the distant ceiling like the fronds of a weeping willow, impeding their progress as they were forced to crash on through.

Bud was walking a short distance behind Tom, head down and starting to grumble. "Good night, maybe these things are petrified spider webs." Glancing up, he saw his friend turn sideways into a recess in the wall. "What are you up to, skipper?" he called out via transiphone.

"I just wanted to see if the stream was pooling any at the base of the wall in here," the answer hummed back.

Bud turned in to the recessed section—a short rounded hollow no more than about twelve feet deep—and suddenly stopped dead. Were his eyes tricking him?

The floor of the stubby cave was flat and open, without boulders or other obstruction. He could see everywhere in the light of his suit lamp, side to side, front to back. But one thing he couldn’t see—any trace of Tom Swift!

MARLENE Jencks lost patience with being patient and sounded the general alarm, ordering the crew of Mod 2 to assemble immediately on the main deck. As the yawning, eye-rubbing crowd accumulated one by one, she briefly explained what had happened, repeating the story in bits and pieces.

"Hain’t seen hide nor hair since?" Chow demanded. "That it?"

"Hank’s out there with whatever it was I saw skulking around at first."

"If anything," commented Rafe Franzenberg. "Please remember, Marlene, my dear—you do have a tendency to become a bit over-exercised."

"I don’t notice you rushing outside to investigate, Rafael!" Jencks snapped back.

"I merely took a moment to put on my spacesuit garb before making an appearance," he replied blandly. "As you can see, I am now ready to take charge of matters."

"Say, where’s Neil MacColter?" asked Dick Folsom suddenly.

"Lookee there!" exclaimed Chow, pointing through the great viewpane.

Two spacesuited figures had appeared near the base unit of the atmos-maker, one half-dragging the other, who seemed unable to walk. As they neared the access ramp, Lori Matthews quietly announced, "It’s Neil and Hank."

Neil pulled the semi-conscious Hank Sterling through the hatchway barrier and lowered him down onto the deck. Both were wearing their helmets for extra warmth, leaving them unsealed and slightly ajar to breathe-in the air provided by Tom Swift’s machine.

"How is he?" asked Dr. Yun, rushing up to help. "I’ll look him over as best I can."

"He was humped over the conveyor conduit, pretty much out of it," explained Neil, panting.

"Did you see anything?" Rafe demanded of MacColter. When the veteran astronaut shook his head, the triple-threat scientist shot Marlene Jencks a condescending look.

Using stimulants from the medical locker, Dr. Yun was quickly able to bring Hank around. "Okay, enough," Hank coughed, sitting upright.

"What happened out there, son?" asked Chow.

The young engineer frowned for a moment, his eyes sweeping the worried faces of his comrades. "I was sure I caught a glimpse of something, like someone trying to duck out of sight behind the equipment. I remember running over to look... after that, I’m not sure. I think I remember being grabbed from behind, someone yanking my helmet back. I don’t know. But my head sure hurts!"

"One needn’t be a medical doctor to determine the cause," said Yun. "There is a swelling bruise back here, where the bottom of your skull meets the top of your neck."

Hank felt of it tentatively, and winced. "Nice place for it! But I don’t know if I banged against my loose helmet when I fell—"

"Or if’n someone banged sumpin against you!" finished Chow grimly.

Hank now stood unsteadily. "Folks, you know Tom put me in charge here while he’s gone. I hate to have to do it, but—I have to ask each one of you to account for where you were, and what you were doing, over the last hour."

"You’ve concluded one of us must be behind these events, have you?" Gretl asked.

"I’ve concluded nothing, Dr. Dornis. All I know is that I’ve got a goose-egg camped out on the back of my head, and it had to come from somewhere."

"Dang right," agreed Chow. "An’ we’re the only people on this here Mars right now—less’n you count Tom and Bud, or mebbe them Red Eye folks—or Martians plain ’n true!"

As the crew traded sober glances, it was Neil who spoke first. "If anyone’d like to know how I happened to be outside—when Marl sounded the beeper, I was lying awake on my cot with my suit still partly on. Couldn’t really sleep, so I was just trying to rest a little. When I overheard what’d happened, I just went on out the hatch—guess no one noticed."

"I thought I had my eye on the hatch the whole time," said Marlene thoughtfully.

"Naw, ma’am, if you’ll pardon my sayin’ it," responded Chow Winkler. "When-so-ever you started in t’tell the story again, you turned toward the person who’d jest come in."

Marlene nodded. "I suppose so. And you, Chow? What were you doing?"

"Aw, ma’am, jest sleepin’ like a bee. An’ don’t ask me whar they got thet expression—I jest say it, I don’t pertend t’ understand it."

Hank chuckled and turned his curious gaze toward Lori Matthews. "I was asleep too," she declared; "and please have the good taste not to ask if I can produce witnesses." As Rafe Franzenberg made a slight sound, she said challengingly: "Oh, I believe the eminent Dr. Franzenberg wishes to speak next!"

"I had roused myself from a fitful sleep and was working on some theorems," he stated.

"Perhaps you wouldn’t mind showing us your work, would you?" demanded Gretl. "Not that we have any reason to distrust you, you big sweet bear of a man, but I have never known you to work between the dinner and breakfast meals. Making a logical distinction between work and effort, of course."

Franzenberg reddened. "And what’s that supposed to mean?"

"Only that you might have been outside the ship for some time, slipping back inside while Marlene went to activate the alarm."

"Petty jealousy," grated the physicist to no one in particular. "The injured pride of the—"

"Enough of that," ordered Hank. "Who’s left?"

"I was quite asleep," reported Dr. Yun.

"As was I," Gretl said.

"I wasn’t," declared Dick Folsom. "I was lying on my cot reading a book. You can look in my cabin—the reading lamp’s still on."

"Well, I guess I’ve done my duty," concluded Hank wryly. "That’s everyone."

But Franzenberg displayed one of his imperious frowns and objected. "No, Sterling. What about our Miss Jencks here?"

Hank gave a look of surprise. "I know where Marlene was, Franzenberg—I was with her."

"Now now, chief, you’re thinking like an engineer, not a theoretical physicist." Dr. Fran-zenberg cleared his throat, as if about to launch into a lecture before a class of inattentive students. "There is what one knows, and what one merely thinks one knows. Am I right?

"The only reason you were out in the airdome in the first place, and thus vulnerable, is that Marlene herself awoke you with a tale—which of course you accepted without evidence—that induced you to leave the ship. What might have happened thereafter? Can we rule out the possibility that she herself donned her extravehicular gear and followed you out, lithely heading around behind your back, concealing herself near the atmos-maker machinery? Then, having accomplished her incomprehensible purpose, who is to say that she didn’t re-enter the Mod, unsuit, and then raise the alarm?—and please don’t bother with the look of outrage, Marlene. I’m only providing a thorough analysis. You’d do the same, no doubt. Assuming you were capable."

Chow clonked over to a sofa and plopped down on it. His plump arms were folded in Texas-wide disgust. "Seems t’me we don’t know nothin’! Exceptin’ mebbe that one ’r two of us don’t much like two ’r three of us."

"Turning us against one another may be precisely what our adversary has in mind," murmured Gretl Dornis.

"That may be what he or she is ac-complishing so far, Dr. Dornis. But I beg you consider that it may only be sheer luck and accident that we are speaking of feelings now—not murder!" Yun exclaimed sharply. "One of my ENCOSS colleagues is dead, and I myself have twice been a target. With his protective suit partially unsealed as it was, Mr. Sterling could easily have died of hypothermia while lying insensible."

"There’s one thing we do know now, and maybe it’s all we really know," said Hank, trying to keep the peace. "—and that’s to be alert."

The ill feelings and suspicions hung over the crew throughout the night and through the day that followed, a long worrisome day that brought no word from Tom and Bud, nor any release from their mysterious imprisonment.

To try to keep up morale, Hank urged the others to continue with their scientific inves-tigations as best they could. To that end they were pleased to find that the strange forces holding down the ship and blocking communication did not prevent them from moving about the local area on foot, even as far as the rim of Coprates Chasma.

"But the thing that makes me madder’n a bent bee is this," grumbled Chow, walking along beside Hank and Dr. Yun a half-mile north of Mod 2. "We don’t know if we’s out o’ touch with Tom and Bud because somethin’ bad happened to ’em—or jest because them space desperados is shootin’ down their signals."

"They became silent hours before the spacecraft was locked down in place," pointed out Dr. Yun. "I suggest an attitude of optimism. I have learned to maintain such an attitude with respect to the fate of my fiancee."

"Guess hopelessness never did do anybody the least dang bit o’ good," concurred the ex-Texan.

Hank Sterling had been quiet for a time. Now he motioned for his two companions to decrease their transiphone radii so their communications could not be heard by others. "I have something to tell you two."

Chow’s eyes bugged out. "Secret stuff?"<